SMPS output problem!!

[vedo35]

Hi guys,
I have Philips dvp3005 dvd player smps. This smps was almost ok. But Only
-24 volt, -12 volt and +12 volt outputs were around 10 volt higer. i mean supposed to give-24 but -38 and -12 volt were 22 volt. I thought i have to change condansers. I had already used but almost new condansers. I used of them now every outputs were doubled out. 3.3volt vere 6.7volt. 5 volt were11 volt. 12 volt were 24 volt others are same too.
I made some pages copy from service manual.

Note: All resistors are normal value. Smps ic working good.

Waiting your ideas.

 

[Nigel Goodwin]

Most likely reason is either C13 or C18, check their ESR (if you have an ESR meter), or check the ripple on them with a scope.

 

[bountyhunter]

Hi guys,
I have Philips dvp3005 dvd player smps. This smps was almost ok. But Only
-24 volt, -12 volt and +12 volt outputs were around 10 volt higer. i mean supposed to give-24 but -38 and -12 volt were 22 volt. I thought i have to change condansers. I had already used but almost new condansers. I used of them now every outputs were doubled out. 3.3volt vere 6.7volt. 5 volt were11 volt. 12 volt were 24 volt others are same too.
I made some pages copy from service manual.

Note: All resistors are normal value. Smps ic working good.

Waiting your ideas.

The design has five output windings on the secondary, but only the 5V and 3.3V contribute to regulating the output voltage via the feedback through the opto coupler. The other winding voltages are dictated by what the feedback on 3.3 and 5V are doing.

When you say the voltages are way high, it sounds as if the feedback could be "open" and the converter is simply running at maximum duty cycle. It could also be that a problem on either the 3.3V or 5V rails could throw everything off.

ALWAYS a good idea to replace every output cap on a switcher when you service it since the ripple current pumps in and out all day long heating them up, so they usually have a short life span. Be sure to use low ESR electrolytics designed for SMPS, generic electrolytics will not work. You need the kind with a guaranteed ESR value specified at 20kHz or higher.

 

[sheldonstv]

ive serviced quite a few of these units-the most common failures are-c13,c14,c18,c19,u3 a til431 can be used here,check the opto by replacement,for high output it is a regular offender,check the value of r7(100r),r10(2k2),r11(3k9),r15(2k2)and d11 replace as iv had failures where the diode reads ok but fails under load also check u1 by replacement....donot forget to replace yr capacitors with hi temp ones (105 deg)